Key points of formulation design for water-based metal anti-corrosion coatings

Water-based metal anti-corrosion coating, in the formulation design process, how to get the best anti-corrosion effect, is worthy of our thinking and exploration of a direction. The following from the individual understanding of anti-corrosion coatings, in the water-based single-group anti-corrosion coating system, talk about the water-based metal anti-corrosion coating formulation design points.
, resin is the key
it is well known that metal corrosion has three elements - water, oxygen and ion

. After contact with the metal substrate, the metal surface is produced by electrochemical principles, which causes the metal to corrode.
anti-corrosion coating by coating the surface of the substrate into a film, separate the metal and moisture, oxygen, ions and other contact, so as to play a corrosion-resistant effect.
we all know that two-part polyurethane coatings and two-part epoxy coatings all have excellent corrosion protection, mainly because they cross-link during film-forming. Through cross-linking reaction, the paint film is unusually dense, better isolated from the metal substrate and the outside world, thus showing excellent corrosion resistance.
, the water resistance of the resin and the adhesion of the substrate play an important role in the process of corrosion prevention.
, to achieve excellent corrosion resistance, dense paint film is necessary.
the lower limit of the resin, the formulation determines the upper limit
in the case of excellent corrosion resistance of the resin, how to further show its advantages, but also depends on the formulation design factors.
1, the effect of pigments:
anti-rust pigments can be divided into two categories: (1) can play a barrier effect, extend the penetration path of the flaky fillers. (2) Fillers that provide anodes, passivate the surface, or deposit to protect the substrate.
addition of anti-rust pigments is undoubtedly of great help to the anti-corrosion properties of conventional anti-corrosion paint film, but in the system of preparing long-term salt spray resistance requirements, it is not always good. For example, in a resin system with high density of paint film, the water resistance and shielding type of the paint film itself are excellent. Some fillers have a certain hydroprosivity, can affect the water resistance of the paint film, and the addition of fillers will also destroy the tightness of the paint film, which is more likely to reduce the overall corrosion resistance.
2, dispersant selection
in the preparation of anti-corrosion coatings, dispersants are often essential. Dispersant is a surfactant, most of which have strong hydroffinity. After the lacquer liquid is filmed, the dispersant does not disappear or react, but remains inside the paint film. This will lead to a decrease in water resistance of the paint film, water and other hydro-ion isolation will also be reduced, thereby reducing the corrosion resistance of the paint film.
3, thickener selection
thickener selection to polyurethane type-based, general alkali-soluble acrylic thickener on water resistance has a certain impact. In addition, polyurethane thickeners have better rheumor properties and help paint films to weed and spread better on substrates.
4, the choice of film-forming additives
In the coating film-forming process, moisture first evaporates, film-forming additives through plasticizing to soften latex particles to avoid cracking, thus playing a role in helping film-forming.
people often think that film-forming additives help the coating into a film, it will evaporate, the coating itself has no effect, in fact, it is not. In the application experiment, the influence of different film-forming additives on coatings is many: the most significant is the hardness climb, followed by water resistance, salt-resistant water, adhesion, salt-resistant fog, etc. have different degrees of impact.
the effect of partial film-forming additives on the properties of lacquer film
From the above experimental results, the performance of solvents on the H1440 system has a great impact, especially on the performance of salt spray resistance. Of course, this is an experiment in the H1440 system, which needs to be further tested in other systems.
5, formula water
formula recommended the use of deionized water, conventional tap water contains a large number of ions and impurities, not only make the stability of the coating bear a certain risk, the anti-corrosion effect of the coating will also have a certain degree of impact.
three-point coating, seven-point construction
paint as a "semi-finished product", construction application is very important. Good paint with good construction applications, in order to really show the performance of the paint.
1, substrate
types of substrates, including substrate treatment a variety of conditions. Different substrates and different substrate treatment methods have a significant impact on the corrosion resistance of lacquer film. However, it is important to ensure that the substrate is clean, dust-free and oil-free.
2, thick film
thick film is one of the important conditions to ensure the corrosion resistance of the coating film, the thicker paint film for the coating can effectively block corrosion factors to provide a guarantee.